It has been my experience, with 40 years as a wedding photographer, that the most forgotten people, when it comes to photos at a wedding, are often the individual parents of the bride and groom.
Most photographers will be sure to include the parents in photos with the bride and groom, but most will never think to inquire about doing groups of the individual dads of the bride or groom with all his brothers and sisters who are present at the wedding. The same is true with the individual moms of the bridal couple.
While you're getting these photos taken, be sure to include any parents and grandparents of those brothers and sisters that are there, in order to capture their entire core family group in photos.
A wedding is almost the perfect place to take these kind of photos with the individual parents and their siblings. Everyone in both families have gathered for the big event, many times from far flung regions of the country.
Their child's wedding may well be the first time the brothers and sisters have gotten together in years. It may be many years in the future before they are ever together again. If the opportunity to take these group photos is passed over because nobody thought much about the importance of this fleeting opportunity, then those photos may end up never being captured. These photos often turn out to be the most important and most appreciated of all the photos I take regularly at the wedding.
I'd be willing to bet that less than 10 percent of wedding photographers plying their trade today know to get these photos for you. You will have to specifically ask for them to be taken, or they just won't be done!
Other important people that most photographers will probably overlook photographing for you at the wedding, unless you give them your written photo request list, are the bride and groom's god parents, groups of the bride and groom's co-workers, high school friends, youth camp friends, fellow fraternity and sorority members, and fellow sports team members for high school or college.
The one thing no wedding photographer can do is look at a room full of total strangers and figure out how they interlock with each other just by looking! I gave up trying to do that after photographing my very first wedding 40 years ago! Now I send each bride an email before the wedding requesting exactly this sort of information, so that I don't end up missing anyone of importance to the bridal couple on their special day.
You will want to see to it that your wedding photographer is thoroughly armed with this often overlook information, so that they will get these photos for you. Remember, your wedding photographer can't read your mind when it comes to who among those present on your wedding are important to you and need to be photographed with you.
You might also help make getting these photos easier for your photographer by making sure that the people who are going to be included in these special group photos are told to be available for the photos being taken when the other groups are done--either before or immediately after the wedding ceremony.
You will not want to be trying to pull these groups together at the reception, because getting them all together at the same time at the reception is often one of the most difficult things you'll do on your wedding day. It is better to avoid doing these photos at the reception altogether, and get them done early in the day.
Also, be sure that all the people to be included in your photos know to stay in the room the photos are being taken until all the groups are done. If someone slips off because they think they are through being photographed and it turns out that they are needed for an impromptu additional last minute group request, everything grinds to a halt, photo-wise, until someone tracks them down and brings the back.
If you aren't careful, this could be repeated over and over again as various people slip outside for a smoke or to use the restroom after their group as been taken. When this happens, it can extend the time needed for the photos by as much as an extra half hour, and that time is probably cutting into your reception time.
A lot of churches today have church services scheduled pretty soon after the wedding concludes, so many times the photographer ends up being rushed, time-wise, on getting the group photos for you. I've had priests tell me immediately after the receiving line concludes, "You have only 20 minutes to get all your groups done. We've got a church service starting soon."
In my email to brides before the wedding date, I always try to avoid having this happen by asking if there is a church service planned for after the wedding, and, if so, how soon will it begin after the wedding . I point out that everyone will need to rush back in immediately if we are crowded for time by the church. Don't let others complicate it for your photographer by them slipping out of the room before all the group photos are taken.